Related papers: On the crystallization onset in white dwarfs
White dwarf stars are subject to various element transport mechanisms that can cause their surface composition to change radically as they cool, a phenomenon known as spectral evolution. In this paper, we undertake a comprehensive…
We investigate the effects of element diffusion on the structure and evolution of low-mass helium white dwarfs (WD). Attention is focused on the occurrence of hydrogen shell flashes induced by diffusion processes during cooling phases.…
A gas giant planet which survives the giant branch stages of evolution at a distance of many au and then is subsequently perturbed sufficiently close to a white dwarf will experience orbital shrinkage and circularization due to star-planet…
The metal abundances in the atmospheres of hot white dwarfs (WDs) entering the cooling sequence are determined by the preceding Asymptotic Giant Branch (AGB) evolutionary phase and, subsequently, by the onset of gravitational settling and…
Based on a compilation of OVI, CIV, SiIV and NV data from IUE, FUSE, GHRS, STIS, and COS, we derive an anti- correlation between the stellar temperature and the high ion velocity shift w.r.t. to the photosphere, with positive (resp.…
DA-type white dwarfs account for 80% of all white dwarfs and represent, for most of them, the ultimate outcome of the typical evolution of low-to-intermediate mass stars. Their internal chemical stratification is strongly marked by passed,…
Neutron-star (NS) - white-dwarf (WD) mergers may give rise to observable explosive transients, but have been little explored. We use 2D coupled hydrodynamical-thermonuclear FLASH-code simulations to study the evolution of WD debris-disks…
Since the Gaia data release 2, several works were published describing a bifurcation in the observed white dwarf colour$-$magnitude diagram for $\mbox{$G_{\mathrm{BP}}$}-\mbox{$G_{\mathrm{RP}}$} > 0$. Some possible explanations in the…
The present work is designed to explore the evolution of helium-core white dwarf (HeWD) stars for the case of metallicities much lower than the solar one (Z=0.001 and Z=0.0002). Evolution is followed in a self-consistent way with the…
Due to their high photospheric density, cool helium-rich white dwarfs (particularly DZ, DQpec and ultracool) are often poorly described by current atmosphere models. As part of our ongoing efforts to design atmosphere models suitable for…
Diffusion of elements in the atmosphere and envelope of a star can drastically alter its surface composition, leading to extreme chemical peculiarities. We consider the case of hot subdwarfs, where surface helium abundances range from…
In this work, we study for the first time the thermal evolution of twin star pairs, i.e., stars that present the same mass but different radius and compactness. We collect available equations of state that give origin to a second branch of…
Current galaxy observations suggest that a roughly linear correlation exists between the [CII] emission and the star formation rate, either as spatially-resolved or integrated quantities. Observationally, this correlation seems to be…
We describe the results of numerical simulations of the dynamics of the boundary layer (BL) between the accretion disk and the surface of a non-magnetic white dwarf (WD) for different viscosities which corresponds to different stages for…
We investigate the luminosity and cooling of highly magnetized white dwarfs where cooling occurs by the diffusion of photons. We solve the magnetostatic equilibrium and photon diffusion equations to obtain the temperature and density…
White dwarf evolution is essentially a gravothermal cooling process, which,for cool white dwarfs, sensitively depends on the treatment of the outer boundary conditions. We provide detailed outer boundary conditions appropriate for computing…
We consider the nature of the fluid-solid phase transition in a polydisperse mixture of hard spheres. For a sufficiently polydisperse mixture crystallisation occurs with simultaneous fractionation. At the fluid-solid boundary, a broad fluid…
We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the…
The precise astrometric measurements of the Gaia Data Release 2 have opened the door to detailed tests of the predictions of white dwarf cooling models. Significant discrepancies between theory and observations have been identified, the…
The freezing of a water rivulet begins with a water thread flowing over a very cold surface, is naturally followed by the growth of an ice layer and ends up with a water rivulet flowing on a static thin ice wall. The structure of this final…